Thyroiditis: Evaluation and Treatment

Thyroiditis is a general term for inflammation of the thyroid gland. The most common forms of thyroiditis encountered by family physicians include Hashimoto, postpartum, and subacute. Most forms of thyroiditis result in a triphasic disease pattern of thyroid dysfunction. Patients will have an initial phase of hyperthyroidism (thyrotoxicosis) attributed to the release of preformed thyroid hormone from damaged thyroid cells. This is followed by hypothyroidism, when the thyroid stores are depleted, and then eventual restoration of normal thyroid function. Some patients may develop permanent hypothyroidism. Hashimoto thyroiditis is an autoimmune disorder that presents with or without signs or symptoms of hypothyroidism, often with a painless goiter, and is associated with elevated thyroid peroxidase antibodies. Patients with Hashimoto thyroiditis and overt hypothyroidism are generally treated with lifelong thyroid hormone therapy. Postpartum thyroiditis occurs within one year of delivery, miscarriage, or medical abortion. Subacute thyroiditis is a self-limited inflammatory disease characterized by anterior neck pain. Treatment of subacute thyroiditis should focus on symptoms. In the hyperthyroid phase, beta blockers can treat adrenergic symptoms. In the hypothyroid phase, treatment is generally not necessary but may be used in patients with signs and symptoms of hypothyroidism or permanent hypothyroidism. Nonsteroidal anti-inflammatory drugs and corticosteroids are indicated for the treatment of thyroid pain. Certain drugs may induce thyroiditis, such as amiodarone, immune checkpoint inhibitors, interleukin-2, interferon-alfa, lithium, and tyrosine kinase inhibitors. In all cases of thyroiditis, surveillance and clinical follow-up are recommended to monitor for changes in thyroid function.

[Thyroiditis: What's new in 2019?]

Thyroiditis is a frequent and mostly benign disease that can sometimes disrupt the thyroid balance. Their diagnosis, as well as their aetiology, is a necessary step in the management of the patients. Painful thyroiditis includes acute thyroiditis of infectious origin and subacute thyroiditis. The first one can be treated by antibiotics or antifungals depending on the germ found. The second one will be treated with non-steroidal anti-inflammatory drugs or corticosteroids. In cases of Hashimoto's thyroiditis with overt hypothyroidism, replacement therapy with L-thyroxine will be adapted to the TSH level. As amiodarone treatment provides dysthyroidism, the thyroid status should be monitored regularly. Hypothyroidism will be treated using thyroid replacement therapy. Hyperthyroidism imposes a stop of amiodarone when it is possible. Treatment with synthetic antithyroid drugs (propyl-thio-uracil) or corticosteroids could be used whether there is an underlying thyroid disease or not. Immunotherapies with anti-PD-1/PDL1 or anti-CTLA-4 can also provide dysthyroidism. A monitoring of the thyroid assessment needs to be done in these patients, even if there are no clinical signs, which are not very specific in this context. The treatment of hypothyroidism will be based on thyroid replacement therapy according to the TSH level and the presence or absence of anti-TPO antibodies. Treatment of symptomatic hyperthyroidism may involve a prescription of beta-blockers, or synthetic antithyroid drugs in case of positive anti-TSH receptor antibodies. In all cases, it is desirable to contact an endocrinologist to confirm the diagnosis hypothesis and to decide on a suitable treatment.

[CME: Thyrotoxicosis and Thyroiditis]

Hyperthyroidism is caused by an increased synthesis of thyroid hormones or release of preformed thyroid hormones due to destruction of thyroid tissue, or there is an exogenous extrathyroidal source. The term thyroiditis describes a heterogeneous group of disorders, which result in destruction of thyroid tissue and release of preformed thyroid hormones. Although a less common condition, a thyroiditis remains an important differential diagnosis for thyrotoxicosis, and a symptomatic therapy is the cornerstone of treatment. Because of the classical triphasic clinical course a 'wait and see strategy' is reasonable, especially during the first and self-limited hyperthyroid phase. Usually a transient hypothyroid phase follows, before the euthyroid function is restored within a year. However, as permanent hypothyroidism may result, regular follow-up and in that case treatment with levothyroxine is mandatory.

[Ginger-partition moxibustion combined with glucocorticoid for thyreoitis at subacute stage: a randomizd controlled trial]

OBJECTIVE

To compare the clinical effects between ginger-partition moxibustion combined with glucocorticoid and simple oral glucocorticoid for thyreoitis at subacute stage.

METHODS

Eighty-one patients were randomly divided into an observation group (41 cases) and a control group (40 cases). In the observation group, ginger-partition moxibustion and hormone were applied. Moxa cones were used at local ashi points, Zusanli (ST 36), Guanyuan (CV 4) and Qihai (CV 6), six cones every point, once every other day and three times a week. Besides, 24 mg methylprednisolone tablets were adopted orally every day, and in two weeks the dose was 16 mg/d, in four weeks 8 mg/d, in six weeks 4 mg/d; all the patients were observed for 8 week. In the control group, simple methylprednisolone was prescribed orally, and the dose, the usage and treatment time were the same as those in the observation group. Erythrocyte sedimentation rate (ESR), triiodothyronine (T3), thyroxin (T4) and ultra-sensitive thyroid stimulating hormone (TSH) before and after treatment were observed in the two groups, as well as fever, the pain of thyroid gland, the regression time of swelling and adverse reaction.

RESULTS

The time of thyroid gland pain relieved of the observation group was earlier than that of the control group [(3.07 ± 0.78) days vs (3.62 ± 0.92) days, P < 0.05]. After treatment, T3, T4 and ESR were declined apparently (all P < 0.01), and TSH was obviously increased in the two groups (both P < 0.01). After 2-week treatment, ESR in the observation group was lower than that in the control group (P < 0.05). After 4-week treatment, T3, T4, TSH and ESR in the observation group were better than those in the control group (all P < 0.05). After 8 weeks, all indices in the observation group were superior to those in the control group, without statistical significance between the two groups (all P > 0.05). The effects of the observation group in 2 weeks, 4 weeks and 8 weeks were better than those in the control group (all P < 0.05). The cured course was shorter in the observation group than that in the control group (P < 0.05). The adverse reaction rate in the observation group was lower than that in the control group [4.9% (2/41) vs 22.5% (9/40), P < 0.05]. Three months later after treatment, the cured patients were followed. There was no recrudescence in the observation group and three patients caught the disease again in the control group, but there was no statistical significance between the two groups (P > 0.05).

CONCLUSION

Ginger-partition moxibustion combined with glucocorticoid achieves better effect than simple oral glucocorticoid for thyreoitis at subacute stage, and the adverse reaction is less, which presents the clinical advantages of the integration of Chinese and western medicine.

Early Hypoparathyroidism Reversibility with Treatment of Riedel's Thyroiditis

BACKGROUND

Riedel's thyroiditis (RT) is a rare, fibroinflammatory condition which induces gradual thyroid gland destruction and adjacent soft-tissue fibrous infiltration. About one- seventh of RT cases are associated with hypoparathyroidism, necessitating long-term therapy for symptomatic hypocalcemia. The reversibility of the parathyroid hormone deficit has not been fully described.

PATIENT FINDINGS

A 40-year-old woman with no prior history of thyroid disease presented with a six month history of progressive thyroid enlargement complicated by worsening dysphagia and positional dyspnea. Her past medical history was remarkable only for retroperitoneal fibrosis. Physical examination revealed a large, hard, non-mobile goiter. Thyroid indices while maintained on levothyroxine were normal, but marked asymptomatic hypocalcemia with an inappropriately normal parathyroid hormone level was noted. Thyroid imaging and fine needle aspiration were consistent with RT. Isthmectomy and subsequent serial corticosteroid and tamoxifen treatment led to rapid symptom improvement. Serum calcium and parathyroid hormone levels returned to the reference range within three months.

SUMMARY

We describe a case of RT in which hypoparathyroidism resolved after treatment targeted the mechanical compression and the fibroinflammatory milieu of the patient's thyroidal disease.

CONCLUSIONS

RT can be associated with hypoparathyroidism that is clinically silent at presentation. Mechanical decompression of the goiter and immunomodulatory therapy can reverse the fibrosclerotic process and lead to rapid recovery of parathyroid gland function, as in this patient. However, in most cases hypoparathyroidism is persistent and requires continued treatment to prevent symptomatic hypocalcemia.

IgG4-related Mikulicz's disease associated with thyroiditis: a case report and review of the literature

PURPOSE

To report an unusual case of IgG4-related Mikulicz's disease associated with thyroiditis.

CASE REPORT

We describe a 25-year-old Chinese man who presented with bilateral, painless swellings of the lachrymal glands, parotid glands, and thyroid nodules. The patient underwent left-sided dacryoadenectomy and the diagnosis of IgG4-related Mikulicz's disease was pathologically confirmed. The size of the right-sided lachrymal gland and parotid glands recovered fundamentally after one month of glucocorticoid therapy.

CONCLUSION

IgG4-related Mikulicz's disease associated with thyroiditis should be considered in the differential diagnosis of bilateral swellings of lachrymal glands, salivary glands, and thyroid nodules. Surgical excision is recommended in order to treat the tumor and to ensure the pathological diagnosis. Glucocorticoid therapy should be considered in association with surgery after removal.

[Non-autoimmune thyroiditis]

The term thyroiditis comprises a group of thyroid diseases characterized by the presence of inflammation, including autoimmune and non-autoimmune entities. It may manifest as an acute illness with severe thyroid pain (subacute thyroiditis and infectious thyroiditis), and conditions in which the inflammation is not clinically evident evolving without pain and presenting primarily thyroid dysfunction and/or goiter (drug-induced thyroiditis and Riedel thyroiditis). The aim of this review is to provide an updated approach on non-autoimmune thyroiditis and its clinical, diagnostic and therapeutic aspects.

Patterns of interferon-alpha-induced thyroid dysfunction vary with ethnicity, sex, smoking status, and pretreatment thyrotropin in an international cohort of patients treated for hepatitis C

BACKGROUND

Interferon-alpha (IFNα)-induced thyroid dysfunction occurs in up to 20% of patients undergoing therapy for hepatitis C. The diversity of thyroid disease presentations suggests that several different pathological mechanisms are involved, such as autoimmunity and direct toxicity. Elucidating the relationships between risk factors and disease phenotype provides insight into the mechanisms of disease pathophysiology.

METHODS

We studied 869 euthyroid patients from the ACHIEVE 2/3 trial, a randomized international clinical trial comparing pegylated-IFNα2a weekly or albumin-IFNα2b every 2 weeks for up to 24 weeks in patients with hepatitis C, genotype 2 or 3, from 136 centers. The study population was 60% male and 55% white. Serum thyrotropin (TSH) and free thyroxine were measured before therapy, monthly during treatment from week 8, and at 4- and 12-week follow-up visits.

RESULTS

Overall, 181 (20.8%) participants had at least one abnormal TSH during the study. Low TSH occurred in 71 (8.2%), of whom 30 (3.5%) had a suppressed TSH below 0.1 mU/L. Hypothyroidism occurred in 53 patients (6.1%), with peak TSH above 10 mU/L in 12 patients (1.4%). Fifty-seven patients had a biphasic thyroiditis (6.6%), with extreme values for the nadir and/or peak TSH in all but one. Medical therapy was given to one thyrotoxic patient, four hypothyroid patients, and 26 biphasic thyroiditis patients. Multivariate logistic regression analysis demonstrated that biphasic thyroiditis is associated with being female and higher pretreatment serum TSH, whereas being Asian or a current smoker decreased the risk of thyroiditis. Hypo- and hyperthyroidism are most strongly predicted by the pretreatment TSH.

CONCLUSIONS

Biphasic thyroiditis accounted for the majority (58%) of clinically relevant IFNα-induced thyroid dysfunction. We confirmed our recent findings in a related cohort that female sex is a risk factor for thyroiditis but not hypothyroidism. Further, in this large multiethnic study, the risk of thyroiditis is dramatically increased, specifically for white women. Smoking was found to be protective of thyroiditis. These results support closer monitoring of women and those with a serum TSH at the extremes of the normal range during therapy so that prompt intervention can mitigate the consequences of thyroid dysfunction associated with IFNα treatment.

Case of concurrent Riedel's thyroiditis, acute suppurative thyroiditis, and micropapillary carcinoma

Riedel's thyroiditis (RT) is a rare chronic inflammatory disease of the thyroid gland. It is characterized by a fibroinflammatory process that partially destroys the gland and extends into adjacent neck structures. Its clinical manifestation can mask an accompanying thyroid neoplasm and can mimic invasive thyroid carcinoma. Therefore, diagnosis can be difficult prior to surgical removal of the thyroid, and histopathologic examination of the thyroid is necessary for a definite diagnosis. The concurrent presence of RT and other thyroid diseases has been reported. However, to our knowledge, the association of RT with acute suppurative thyroiditis and micropapillary carcinoma has not been reported. We report a rare case of concurrent RT, acute suppurative thyroiditis, and micropapillary carcinoma in a 48-year-old patient.

Thyroid disease in chronic hepatitis C infection treated with combination interferon-α and ribavirin: management strategies and future perspective

OBJECTIVE

Hepatitis C virus (HCV) infection is one of the major epidemics afflicting young people in both developed and developing countries. The most common endocrine disorder associated with this infection, especially in conjunction with interferon-α (IFN-α)-based therapy, is thyroid disease (TD). This review examines the development of TD before, during, and after the completion of treatment with combination IFN-α and ribavirin (RBV) for chronic HCV infection. We also summarize the current understanding of the natural history of the condition and propose management and follow-up guidelines.

METHODS

PubMed was searched up to June 30, 2011 for English-language publications that contained the search terms "hepatitis C virus," "chronic hepatitis C," "HCV," "thyroid disease," "thyroiditis," "autoimmunity," "interferon-alpha," and "ribavirin." Additional publications were identified from the reference lists of identified papers. The included studies were original research publications and included combination IFN-α and RBV use in patients that developed TD.

RESULTS

The prevalence of TD before combination IFN-α and RBV therapy ranges from 4.6 to 21.3%; during therapy, 1.1 to 21.3%; and after therapy, 6.7 to 21.3%. The most common TD is thyroiditis. Thyroid function testing (TFT) frequency and diagnostic criteria for various thyroid conditions are not standardized, and many of the existing studies are retrospective.

CONCLUSION

Patients undergoing this therapy should be assessed with a standardized protocol to appropriately detect and manage developed TD. Based on the currently available literature, we recommend that patients receiving combination interferon-α and RBV therapy undergo monthly thyrotropin (TSH) level testing.

[Thyroiditis]

The diagnosis of thyroiditis encompasses a broad spectrum of thyroid disorders. Analysis of signs and symptoms, biochemical changes, neck ultrasound characteristics and radioactive iodine uptake values allows an accurate diagnosis. Recent studies of the whole genome have helped to identify many susceptibility genes for autoimmune thyroiditis. However, none of these genes contribute to a significant increase in risk of developing this thyroiditis. Clinical awareness of the characteristic presentations of exceptional thyroiditis (acute suppurative thyroiditis, Riedel's thyroiditis) is an important issue. Selenium administration seems to be beneficial for reducing the incidence of thyroiditis. Finally, certain drug-induced thyroiditis remains a therapeutic challenge for the physician.

[Hashimoto's thyroiditis(chronic thyroiditis), IgG4-related thyroiditis]

Hashimoto's thyroiditis emerges in patients who have genetic preponderance such as SNPs of CTLA-4 and risk factors such as excess intake of iodine, pregnancy or postpartum period, and smoking. Such risk factors also affect the entire clinical course. One of the major outcomes in Hashimoto's thyroiditis appears to be increased in cardio-vascular risks through subclinical hypothyroidism and concomitant metabolic syndrome, but in most cases, treatment with L-T4 has little effects on cardio-vascular benefit or quality of life. The pregnant women also have risks for obstetric complications and postpartum thyroid dysfunction. The women who have anti-TPO antibodies, type 1 diabetes, or previous history of post-partum thyroid dysfunction are recommended to be measured their TSH. It is noteworthy that Hashimoto's thyroiditis is sometimes complicated with encephalopathy, papillary carcinoma, or IgG4-related thyroiditis. IgG4-related thyroiditis is partly similar but partly discerned from a variant of Hashimoto's thyroiditis. The pathogenetic roles of this variant on autoimmune-based thyroiditis remain unclear.

Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to update the guidelines for the management of thyroid dysfunction during pregnancy and postpartum published previously in 2007. A summary of changes between the 2007 and 2012 version is identified in the Supplemental Data (published on The Endocrine Society's Journals Online web site at http://jcem.endojournals.org).

EVIDENCE

This evidence-based guideline was developed according to the U.S. Preventive Service Task Force, grading items level A, B, C, D, or I, on the basis of the strength of evidence and magnitude of net benefit (benefits minus harms) as well as the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

The guideline was developed through a series of e-mails, conference calls, and one face-to-face meeting. An initial draft was prepared by the Task Force, with the help of a medical writer, and reviewed and commented on by members of The Endocrine Society, Asia and Oceania Thyroid Association, and the Latin American Thyroid Society. A second draft was reviewed and approved by The Endocrine Society Council. At each stage of review, the Task Force received written comments and incorporated substantive changes.

CONCLUSIONS

Practice guidelines are presented for diagnosis and treatment of patients with thyroid-related medical issues just before and during pregnancy and in the postpartum interval. These include evidence-based approaches to assessing the cause of the condition, treating it, and managing hypothyroidism, hyperthyroidism, gestational hyperthyroidism, thyroid autoimmunity, thyroid tumors, iodine nutrition, postpartum thyroiditis, and screening for thyroid disease. Indications and side effects of therapeutic agents used in treatment are also presented.

Painless thyroiditis complicating with hypercalcemic encephalopathy

BACKGROUND

Severe hypercalcemia has rarely been reported in patients with hyperthyroidism. Although the pathogenesis is not clear; it is believed to be due to activation of osteoclasts resulting in excessive bone resorption.

OBJECTIVE

To recognize the unusual cause of hypercalcemia from painless thyroiditis, which could manifest with transient hyperthyroidism in the early stage.

CASE REPORT

A 70-year-old woman presented with watery diarrhea, nausea and vomiting and significant weight loss for two months. Initially, she was misdiagnosed as having Graves'disease from her clinical presentation and thyroid function tests. Oral propylthiouracil was given to treat hyperthyroidism. However two weeks after discharge, she developed altered consciousness due to severe hypercalcemia. After combined treatment of hypercalcemia and severe hyperthyroidism, her symptoms resolved quickly. Later on, her thyroid function tests switched to subclinical hypothyroid at two months after initial presentation. No concurrent pathological conditions could be found to explain the other causes of hypercalcemia. Therefore, painless thyroiditis complicated with severe hypercalcemia was subsequently diagnosed based on her clinical course.

CONCLUSION

Hypercalcemic encephalopathy is an uncommon manifestation of hyperthyroidism that should be kept in mind in patients who demonstrated clinical pictures of hyperthyroidism and alteration of consciousness. Moreover the present case emphasizes the consideration of painless thyroiditis as a differential diagnosis of hyperthyroidism because anti-thyroid medications were not indicated in this condition.

Clinical review: Riedel's thyroiditis: a clinical review

CONTEXT

Riedel's thyroiditis is a rare inflammatory process involving the thyroid and surrounding cervical tissues and is associated with various forms of systemic fibrosis. Riedel's presentation is complex, including a thyroid mass associated with local symptoms, characteristic biochemical abnormalities such as hypocalcemia and hypothyroidism, as well as the involvement of a wide range of other organ systems. Diagnosis of Riedel's thyroiditis requires histopathological confirmation, but due to high complication rates, the role of surgical intervention is limited to airway decompression and diagnostic tissue retrieval. Unique among processes of the thyroid, Riedel's is commonly treated with long-term antiinflammatory medications to arrest progression and maintain a symptom-free course. Due to its rarity, Riedel's may not be immediately diagnosed, so clinicians benefit from recognizing the constellation of findings that should make prompt diagnosis possible.

EVIDENCE ACQUISITION

A review of print and electronic reviews was conducted. Source references were identified, and available literature was reviewed. A search of the PubMed database using the search term "Riedel's thyroiditis" was cross-referenced with associated clinical findings, systemic fibrosis diagnoses, and therapeutic search terms. Because most of the literature consisted of case reports and very small series, inclusion of identified articles was based on clinical descriptions of the subjects included and the criteria for diagnosis reported. More weight was attributed to series, using contemporary criteria for diagnosis. Case reports were included if the diagnosis was clear and clinical presentation was unique to illustrate the spectrum of disease.

EVIDENCE SYNTHESIS

Because the majority of therapeutic intervention data were based upon case reports and very small series, an evidence-based approach was problematic, but information is presented as objectively and with as much balance as the limited quality of the data allows.

CONCLUSIONS

Clinical awareness of the characteristic presentations of Riedel's thyroiditis should enhance our ability to make this diagnosis in a timely and focused manner. Recognition of certain clinical finding patterns will increase the likelihood of recognizing Riedel's thyroiditis promptly. Local restrictive or infiltrative symptoms out of proportion to a demonstrable mass or simultaneous biochemical deficiencies especially of calcium should lead the clinician to consider this diagnosis. Likewise in this setting, the surgeon alert to this possibility may minimize overly aggressive surgical intervention, thus avoiding complications. Once Riedel's thyroiditis is diagnosed, the application of antiinflammatory therapies may greatly enhance the clinical outcome. Understanding the pathophysiological relationship of this entity with other forms of systemic fibrosis and the role that IgG4 may play in this process should result in enhanced diagnostic and therapeutic tools in the future.

Environmental triggers of thyroiditis: hepatitis C and interferon-α

Autoimmune thyroid diseases (AITD) are postulated to develop as a result of a complex interplay between several genetic and environmental influences. The pathogenesis of AITD is still not clearly defined. However, among the implicated triggers (e.g. iodine, infections, medications), more recent data confirmed strong associations of AITD with the hepatitis C virus (HCV) infection and interferon-α (IFNα) therapy. Moreover, it is likely that HCV and IFN act in synergism to trigger AITD in patients. Indeed, approximately 40% of HCV patients develop either clinical or subclinical disease while receiving IFNα. Interferon induced thyroiditis (IIT) can manifest as non-autoimmune thyroiditis (presenting as destructive thyroiditis, or non-autoimmune hypothyroidism), or autoimmune thyroiditis [presenting with clinical features of Graves' disease (GD) or Hashimoto's thyroiditis (HT)]. Although not yet clearly understood, it is thought that IFNα can induce thyroiditis via both immune stimulatory and direct toxic effects on the thyroid. In view of the high frequency of IIT, routine screening and surveillance of HCV patients receiving IFNα is recommended to avoid the complications, such as cardiac arrhythmias, associated with thyrotoxicosis. In summary, IIT is a common clinical problem that can be readily diagnosed with routine thyroid function screening of HCV patients receiving IFN. The treatment of IIT consists of the standard therapy for differing clinical manifestations of IIT such as GD, HT, or destructive thyroiditis. However, anti-thyroid medications are not recommended in this setting since they can potentially be hepatotoxic.

Thyroid hormones affect serum angiotensin I converting enzyme levels

Serum angiotensin I converting enzyme (ACE) was measured in 10 patients with Graves' disease and 2 with thyroiditis during different stages of the diseases. The effect of thyroxine on serum ACE levels was also recorded in 12 patients with thyroid cancer, who were on thyroxine suppression. Serum ACE levels correlated positively with clinically assessed thyroid function and peripheral thyroid hormone levels, especially during hyper- or hypofunction. ACE was measured both with an enzyme kinetic and a new, quantitative inhibitor binding assay. The methods gave similar results, which indicates that ACE increments during thyroid hyperfunction were quantitative, and not a result of increased enzyme activity. Serum ACE increments associated with high lysozyme concentrations are signs of immunologic activation or proliferation of monocytic cells. In this study there was no correlation between the two enzymes, which may indicate either increased synthesis or possibly shedding of ACE from endothelial cells or delayed metabolic clearance of this enzyme. Serum ACE measurements may provide a useful tool for assessing thyroid function and the effect of thyroxine treatment.

Interferon alpha treatment and thyroid dysfunction

Interferon alpha (IFN alpha) is the cornerstone therapeutic agent for chronic hepatitis C virus (HCV) infection. Prospective studies have shown that up to 15% of HCV patients receiving IFN alpha develop clinical thyroid disease, and up to 40% become thyroid antibody positive. In some cases IFN-induced thyroiditis (IIT) may result in discontinuation of interferon therapy; thus, IIT represents a major clinical problem for hepatitis C patients receiving IFN alpha therapy. Recently, the mechanisms leading to the development of IIT have begun to be unraveled. It is now clear that HCV itself plays a role in the disease. Moreover, recent data suggest the IFN alpha precipitates thyroiditis by both immune modulatory mechanisms and direct thyroid toxic effects. Genetic factors also play a major role in the etiology of IIT. IIT can manifest both as clinical autoimmune thyroiditis (ie, Hashimoto's thyroiditis and Graves' disease) and as nonautoimmune thyroiditis (ie, destructive thyroiditis). Early detection and therapy of these conditions are important to avoid complications of thyroid disease such as cardiac arrhythmias. This article reviews the epidemiology and clinical manifestations of IIT and the mechanisms causing IIT, focusing on the role of HCV.

Acute thyroiditis of odontogenic origin

If an abscess is not able to establish drainage through the skin surface or into the oral cavity, it may spread diffusely through fascial planes of the neck's soft tissue. Once the infection descends into the submandibular space, it may extend to the lateral pharyngeal space, and then to the retro-pharyngeal space. From here, it may reach the thyroid gland. The authors here describe a case of submandibular phlegmon derived from a periapical abscess of inferior premolar, which has reached the thyroid gland. The damage caused to the gland resulted in the release of a conspicuous quantity of thyroid hormones, thus causing a thyrotoxic pattern: temperature, cutaneous pallor, excessive perspiration, tremor, tiredness, weight loss, increased appetite, and tachycardia. Additionally, the gland's edema caused dysphagia and dysphonia commonly seen with thyroid gland enlargement. After dental drainage and appropriate anti-inflammatory and antibiotic therapy, administration of oral beta-blockers and corticosteroid therapy were performed to counteract thyrotoxicosis in order to prevent recurrences. Finally, a root canal was performed once the thyrotoxicosis had been resolved.

Thyroiditis

Thyroiditis is an inflammation of the thyroid gland that may be painful and tender when caused by infection, radiation, or trauma, or painless when caused by autoimmune conditions, medications, or an idiopathic fibrotic process. The most common forms are Hashimoto's disease, subacute granulomatous thyroiditis, postpartum thyroiditis, subacute lymphocytic thyroiditis, and drug-induced thyroiditis (caused by amiodarone, interferon-alfa, interleukin-2, or lithium). Patients may have euthyroidism, hyperthyroidism, or hypothyroidism, or may evolve from one condition to another over time. Diagnosis is by clinical context and findings, including the presence or absence of pain, tenderness, and autoantibodies. In addition, the degree of radioactive iodine uptake by the gland is reduced in most patients with viral, radiation-induced, traumatic, autoimmune, or drug-induced inflammation of the thyroid. Treatment primarily is directed at symptomatic relief of thyroid pain and tenderness, if present, and restoration of euthyroidism.

[Treatment of hyperthyroidisms in Brazzaville Teaching Hospital, Congo]

Between January 1994 and December 2003, a total of 118 patients (MIF = 1/13) with thyrotoxicosis was studied at the endocrine and metabolic diseases unit of the Centre Hospitalier Universitaire de Brazzaville, in Congo. 72 patients (61%) had Graves' hyperthyroidism, 23 (19.6%) had toxic multinodular goitre while the rest had toxic adenoma (7.6%), and thyroiditis (4.2%). The mean age was 26.6 +/- 7.9 years for Graves' cases and 49.4 +/- 9.3 years for toxic multinodular goitre cases. The clinical presentation was similar to other reported series. Thirty-seven patients (31.3%) did not return after the first admission. All patients responded to carbimazole therapy and no major side-effect was recognized. Ten patients (8.5%/) underwent subtotal thyroidectomy, among them one developed hypothyroidism a year later. The result of this study shows that thyrotoxicosis is not a rare condition in Congo.

[Thyroiditis: an approach for the practitioner]

Thyroiditis represent commonly encountered thyroid disorders in clinical medicine. Autoimmune thyroiditis is frequent with various forms: Hashimoto's thyroiditis, subacute thyroiditis with lymphocytic and post-partum variants. In the absence of any changes in volume and function, Hashimoto's thyroiditis can be seen in a setting of a thyroid nodule, elevation of thyroid autoantibodies and by the pathologist in surgical or cytological materials. Presenting with fever, cervical pain and subtle signs of hyperthyroidism, subacute thyroiditis (De Quervain) represents often a challenge for an early recognition and an appropriate treatment. Acute thyroiditis and Riedel's thyroiditis are very uncommon, with cervical mass and pain.

[Physical therapy in the complex treatment of thyroiditis]

Pathogenetic approaches (clinico-anatomic, structural features of thyroid epithelium, echographic signs, functional activity of the thyroid) served the basis for division of inflammatory diseases into 4 groups. A wide spectrum of physiotherapeutic procedures are suggested for treatment of thyroiditis. There may be different combination of physiotherapy with medication. The response was assessed by ultrasonography and dopplerography evidence. Physiotherapy potentiates the action of drugs and can be also used as monotherapy in dysfunctional thyroid pathology.

Inflammatory thyroid disorders

Inflammatory thyroid disorders encompass a broad spectrum of diseases that are generally self-limited, and relatively easy to diagnose and manage. Autoimmune subtypes are by far the most commonly encountered diagnoses and create the most confusion because of simultaneous overlap and the potential for interconversion among the subtypes. The otolaryngologist will frequently see these disorders and provide valued consultative care and surgical intervention as needed.

[Acute thyroiditis]

We review the pathophysiology, clinical features and therapy of acute thyroiditis. Four cases are reported stressing the role of fine needle aspiration for the diagnosis of this clinical entity.

Postpartum thyroiditis and autoimmune thyroiditis in women of childbearing age: recent insights and consequences for antenatal and postnatal care

Postpartum thyroiditis is a syndrome of transient or permanent thyroid dysfunction occurring in the first year after delivery and based on an autoimmune inflammation of the thyroid. The prevalence ranges from 5-7%. We discuss the role of antibodies (especially thyroid peroxidase antibodies), complement, activated T cells, and apoptosis in the outbreak of postpartum thyroiditis. Postpartum thyroiditis is conceptualized as an acute phase of autoimmune thyroid destruction in the context of an existing and ongoing process of thyroid autosensitization. From pregnancy an enhanced state of immune tolerance ensues. A rebound reaction to this pregnancy-associated immune suppression after delivery explains the aggravation of autoimmune syndromes in the puerperal period, e.g., the occurrence of clinically overt postpartum thyroiditis. Low thyroid reserve due to autoimmune thyroiditis is increasingly recognized as a serious health problem. 1) Thyroid autoimmunity increases the probability of spontaneous fetal loss. 2) Thyroid failure due to autoimmune thyroiditis-often mild and subclinical-can lead to permanent and significant impairment in neuropsychological performance of the offspring. 3) Evidence is emerging that as women age subclinical hypothyroidism-as a sequel of postpartum thyroiditis-predisposes them to cardiovascular disease. Hence, postpartum thyroiditis is no longer considered a mild and transient disorder. Screening is considered.

Thyroid disease in HCV carriers undergoing antiviral therapy with interferon plus ribavirin

High prevalence of thyroid autoantibodies, with or without overt thyroiditis, has been described in hepatitis C patients, particularly in those undergoing alpha-interferon treatment. The aim of this study was to describe the frequency and clinical outcome of thyroid disease in a cohort of HCV carriers before and during combination therapy with interferon plus ribavirin. Between May, 1997, and May, 1999, 111 previously untreated (naive) patients were treated with a-interferon plus ribavirin for 6 or 12 months. Of those, 67 (60%) patients were male and 44 (40%) female. Thyroid function was evaluated in all patients by testing free T4, TSH and antiTPO within 30 days prior to treatment, 90 days after treatment was initiated, and 6 months after treatment was concluded. Abnormal thyroid tests were observed in 4 (3.6%) patients--1 male and 3 female--before the onset of antiviral treatment. Three patients were already undergoing T4 replacement due to Hashimoto thyroiditis and 1 patient had positive antiTPO with normal free T4 and TSH. All 4 patients completed the treatment regime for HCV, but required hormone replacement. Among the patients with a normal thyroid function test prior to treatment (107 cases), 5 (4.6%) developed thyroid test abnormalities; 2 patients had hypothyroidism due to autoimmune thyroiditis; 1 patient became positive for antiTPO antibodies but thyroid function remained normal, and 2 patients had subacute thyroiditis. Four of these patients (80%) were female and 1 was male (20%). A family history of thyroid disease was strongly predictive of thyroid abnormalities during antiviral treatment. In conclusion, there is a low prevalence of thyroid function abnormalities in HCV carriers with no prior antiviral treatment. Family history of thyroid disease reinforces the special attention to thyroid abnormality development before considering antiviral therapy. Subacute thyroiditis during combination therapy was observed, but its pathogenesis is still unknown. Evaluation of thyroid function during and after antiviral treatment is strongly recommended because thyroid related symptoms can be easily misinterpreted as medication side effects.

Recognizing, understanding, and treating postpartum thyroiditis

Postpartum thyroiditis is the most common endocrinologic disorder, with an incidence that varies geographically from 5% to 10%. It has important clinical sequelae including symptoms of hyperthyroidism, hypothyroidism, and depression. Long-term follow-up of women who experience postpartum thyroiditis reveals a high recurrence rate in subsequent pregnancies. Postpartum thyroiditis is an autoimmune disorder, and thyroid antibody-positive women in the first trimester have a 33% to 50% chance of developing thyroiditis in the postpartum period. Whether or not to screen for postpartum thyroiditis remains controversial.

Thyroiditis: differential diagnosis and management

Thyroiditis is a group of inflammatory thyroid disorders. Patients with chronic lymphocytic thyroiditis (also referred to as Hashimoto's thyroiditis) present with hypothyroidism, goiter, or both. Measurement of serum thyroid autoantibodies and thyroglobulin confirms the diagnosis. Subacute granulomatous thyroiditis (sometimes referred to as de Quervain's disease) is a self-limited but painful disorder of the thyroid. Physical examination, elevated erythrocyte sedimentation rate, elevated thyroglobulin level and depressed radioactive iodine uptake (RAIU) confirm the diagnosis. Subacute lymphocytic thyroiditis (silent thyroiditis) is considered autoimmune in origin and commonly occurs in the postpartum period. Symptoms of hyperthyroidism and depressed RAIU predominate. Acute (suppurative) thyroiditis is a rare, infectious thyroid disorder caused by bacteria and other microbes. The rare, invasive fibrous thyroiditis (Riedel's thyroiditis) presents with a slowly enlarging anterior neck mass that is sometimes confused with a malignancy.

Hypoparathyroidism secondary to Riedel's thyroiditis. A case report and a review of the literature

Riedel's thyroiditis is a rare condition in which the thyroid gland is replaced by fibrous tissue. Fibrosis in various distant sites is a possible concomitant event. We report a case of Riedel's thyroiditis complicated by mediastinal fibrosis, a tumefactive fibro-inflammatory lesion of the neck and primary hypothyroidism. A review of the literature in which only 8 previous cases of hypoparathyroidism secondary to Riedel's thyroiditis have been recounted concludes the report.

Postpartum thyroiditis

Postpartum thyroiditis (PPT) is a syndrome of transient thyroid dysfunction occurring in the first postpartum year. A thyrotoxic phase may be brief and unnoticed before a more long-lasting hypothyroid phase occurs. The incidence is variably reported, ranging from 1.9% to 16.7%, perhaps reflecting racial or geographical differences in the distribution of genetic or environmental risk factors such as the titre of thyroid antibodies and the dietary intake of iodine. The syndrome is an autoimmune disorder, strongly associated with the presence of thyroid microsomal antibody in serum. The thyrotoxic phase may be distinguished from Graves' disease by the finding of low, rather than high, uptake of radioactive iodine or technetium in the thyroid. Screening may be valuable in women with other autoimmune disorders such as Type 1 diabetes mellitus. Treatment should be tailored to the symptoms. Significant thyrotoxic problems should be managed with beta-blocking agents, but severe hypothyroid symptoms should be treated with the short-term replacement thyroxine. A small proportion of affected women will remain permanently hypothyroid. There is also a significant risk of recurrent disease after a subsequent pregnancy.